Can I mechanically galvanize fasteners that are very long in length?

Mechanical galvanizing (ASTM B695) is a process in which fasteners are tumbled in a barrel with a mixture of water, zinc powder, other chemicals, and glass impact beads. As the parts are tumbled in the slurry, the zinc is “cold welded” to the fasteners. While some mechanical galvanizers can process parts that over a foot long, and potentially up to a couple feet long, there are some difficulties processing long parts and especially any substantial quantity of long parts.

The process of mechanical galvanizing requires the parts to not only roll, but also tumble end over end thus acquiring the thickness and adhesion required by mechanical galvanizing specification. Larger parts do not tumble very well and thus are very difficult to coat. And when they do tumble, due to their long length and large weight, they can break the glass impact media used in the mechanical galvanizing process. The only effective way to mechanically galvanize parts over roughly 12” in length is to mix them with smaller product that will allow the process to be correctly performed and without damaging/hampering the process.

Some mechanical galvanizers will entertain longer parts, but only on a case-by-case basis and in limited quantities. For parts that number over 5 or 10 total quantity in a batch there would need to be special consideration by the mechanical galvanizer for the amount of product, length, and weight of each bolt. Large anchor bolts and construction fasteners that need corrosion protection over 12” long can be efficiently and successfully produced with a hot-dip galvanized finish that is more resilient and is actually bonded to the steel at a molecular level.

Portland Bolt performs hot-dip galvanizing within our 140,000 square foot manufacturing facility. Our in-house hot-dip galvanizing line is designed specifically for threaded fasteners. Hot-dip galvanizing is not restricted to the short length limitations that mechanical galvanized products are limited to. Contact us for your galvanized anchor bolt and nonstandard fastener requirements.

Written ,


    What is a difference in corrosion protection: mechanical galvanized threaded fasteners vs. hot-dip galvanized threaded fasteners?
    Where is advantage/disadvantage for threaded fasteners?
    How big is difference in price?

    @Waldemar- Generally speaking, hot dip galvanizing will be a better corrosion option, and it will also be less expensive. However, that doesn’t mean that it is the best and cheapest option for all applications. We’d suggest that you discuss the specifics with your project engineer to determine which is best.

Leave a Reply

Your email address will not be published. Required fields are marked *